I highly recommend that you make an appointment with a board certified plastic surgeon for an examination. There could be many reasons that may have caused the asymmetry ranging from implant malposition or issues with integrity, capsular contracture, or even change in your weight/breast shape. Best to get a full evaluation.
See your surgeon
You should make an appointment with your plastic surgeon for an in person examination as the symptoms you are describing could indicate a number of things. More pictures would be helpful, but having your doctor examine you and prescribe further treatment is probably necessary.
It really depends on what kind of augmentation you had and if the same thing was done on both sides and sometimes its because you are right or left handed. If the breast looks different and feels different, it is important to maintain follow up with your doctor and have your concerns addressed in person as well. Best of luck, MMT